A force field for vanadium-oxos was developed and tested with a variety of complexes with coordination numbers of 5 or 6 and formal oxidations states of +4 or +5 on the metal. Similarly, a semiempirical quantum mechanical method for transition metals was extended to vanadium. In this research soft and hard ligands were studied, as were ligands coordinated through single, multiple, and dative bo...

Oxo- and imido-vanadium(V) metal complexes supported by bis(phenolate)-functionalized N-heterocyclic carbene (NHC) ligands were synthesized structurally identified. In the presence of [(Ph3P)2N]Cl ([PPN]Cl), saturated NHC oxo-vanadium showed activity in coupling CO2 cyclohexene oxide (CHO) into cis-cyclohexene carbonate (cis-CHC). More importantly, complex bearing less electron-donating benzann...

A series of oxovanadium(V) complexes containing amine pyridine(s) phenolate ligands [ONN] (2a-f) have been synthesized in high yields (68-83%) by reacting VO(O(n)Pr)3 with 1.0 equiv. of the ligands in CH2Cl2. These complexes were characterized by (1)H, (13)C and (51)V NMR spectroscopy and elemental analysis. X-ray structural analysis for 2a, 2c and 2d revealed that these complexes adopt a six-c...

The crystal structure of the title compound, [Cr(C8H8NO)3], is isotypic with the vanadium(III) analogue. The asymmetric unit consists of one Cr(3+) cation and three N-methyl-salicylaldiminate anions. The metal cation is octa-hedrally coordinated by three N,O-chelating N-methyl-salicylaldiminate ligands, leading to discrete and neutral complexes. In the crystal, neighbouring complexes are linked...

An aqueous deposition process for V(6)O(13) films is developed whereby the vanadium oxidation state is continuously controlled throughout the entire process. In the precursor stage, a controlled wet chemical reduction of the vanadium(V) source with oxalic acid is achieved and monitored by (51)Vanadium Nuclear Magnetic Resonance ((51)V-NMR) and Ultraviolet-Visible (UV-Vis) spectroscopy. The resu...

A series of mononuclear V((V)), V((IV)) and V((III)) complexes were investigated by V L-edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The spectra show significant sensitivity to the vanadium oxidation state and the coordination environment surrounding the vanadium center. The L-edge spectra are interpreted with the aid of the recently developed Density Functional Theory/...

A series of 11 oxovanadium(V) complexes mimicking the active site of vanadium haloperoxidases have been investigated by (51)V magic angle spinning NMR spectroscopy and density functional theory (DFT). The MAS spectra are dominated by the anisotropic quadrupolar and chemical shielding interactions; for these compounds, C(Q) ranges from 3 to 8 MHz, and delta(sigma) is in the range 340-730 ppm. Th...

Bis(peroxo)vanadium(V) complexes are widely investigated as anticancer agents. They exert their antitumor and cyctotoxic effects through inhibition of tyrosine phosphatases and DNA cleavage, respectively. The latter process remains poorly understood. The mechanism of DNA cleavage by NH(4)[(phen)V(O)(eta(2)-O(2))(2)] (phen = 1,10-phenanthroline) was investigated. Kinetic studies on DNA cleavage ...

The oxovanadium(IV) complexes LVO and L'VO (L = dianion of 5,14-dihydro-6,8,15.17tetramethyldibenzo[b.i][l,4.8,ll]tetraazacyclotetradecine. H2L. and L' = dianion of 5.14-dihydro-6,15-dimethyl-8,17-diphenyldibenzo[b,i][l,4,8,1 l]tetraazacyclotetradecine, H2L') are redox active as indicated by cyclovoltammetric measurements and confirmed by preparative methods: Reversible oxidation to the corresp...

Macrocyclic Schiff base ligands (HDAA) and (EDAA) have been synthesized by condensation of Hydrazinedihydrochloride and Ethylenediamine with acetyl acetone respectively in 1:1 molar ratio in ethanolic solution. Further the vanadium complexes were synthesized by refluxing ligands with [VO(acac)2] in1:1 molar ratio in ethanolic medium. The microanalytical analysis have been obtained and UV, IR, H...